Notebook computer having keyboard decoding in palmrest

ABSTRACT

A portable information handling system, user interface components thereof, and methods of user control interface and assembly are disclosed. In one embodiment a keyboard assembly, including a large plurality of contacts for a keyboard matrix, connects directly to a palmrest assembly. The palmrest assembly includes a keyboard controller, which decodes keystrokes and then passes the decoded keystrokes to, e.g., an I/O controller on the motherboard of the portable information handling system. This results in greatly improved layout and usage of the motherboard routing spaces, improved reliability, and simplified assembly.

BACKGROUND

The description herein relates to portable information handling systemsand the keyboard interconnects for such systems.

As the value and use of information continue to increase, individualsand businesses seek additional ways to process and store information.One option available to users is information handling systems. Aninformation handling system (IHS) generally processes, compiles, stores,and/or communicates information or data for business, personal, or otherpurposes thereby allowing users to take advantage of the value of theinformation. Because technology and information handling needs andrequirements vary between different users or applications, IHSs may alsovary regarding what information is handled, how the information ishandled, how much information is processed, stored, or communicated, andhow quickly and efficiently the information may be processed, stored, orcommunicated. The variations in IHSs allow for IHSs to be general orconfigured for a specific user or specific use such as financialtransaction processing, airline reservations, enterprise data storage,or global communications. In addition, IHSs may include a variety ofhardware and software components that may be configured to process,store, and communicate information and may include one or more computersystems, data storage systems, and networking systems.

Portable IHSs, such as “laptop” or “notebook” computers, generally placeall or most of the components of the system in a single chassis of smallenough dimensions and weight to be conveniently carried in a briefcaseor similarly sized carrying case.

SUMMARY

A portable IHS comprises a housing enclosing a motherboard, a palmrestassembly coupled to the housing and comprising a keyboard controller,and a keyboard assembly coupled to the palmrest assembly such that thekeyboard controller receives keystroke signals from the keyboardassembly. A first bus couples the keyboard controller to the motherboardthrough the palmrest assembly, with the keyboard controller transmittingdecoded keystrokes to the motherboard over the bus.

In another aspect of the disclosure, a computer palmrest assemblycomprises a circuit board, a keyboard controller mounted to the circuitboard, and a connection point to receive a keyboard assembly. Theconnection point has a plurality of electrical connections connectedthrough the circuit board to the keyboard controller. The palmrestassembly further comprises a first connector to pass decoded keystrokeinformation from the keyboard controller to another device located offthe palmrest assembly.

In yet another aspect of the disclosure, a keyboard comprises a rigidlower frame having a connection tab along its bottom edge for mechanicalconnection to a palmrest assembly, and a conductor matrix overlying therigid frame and defining conductor crossing points substantially alignedwith key locations on the keyboard. The conductor matrix comprisesextensions of the matrix conductors onto the connection tab to form aplurality of contacts for electrical connection of the keyboard to thepalmrest assembly.

In still another aspect of the disclosure, a diagnostic system for aportable computer comprises a motherboard having a first I/O controller,a palmrest assembly having a second I/O controller, and a bus connectionlinking the first I/O controller to the second I/O controller throughthe motherboard and palmrest assembly. A keyboard assembly connects tothe palmrest assembly. A loopback circuit on the palmrest assembly andkeyboard assembly allows the second I/O controller to test thecontinuity of the connection between the keyboard assembly and thepalmrest assembly.

Also disclosed is a method of coupling a keyboard assembly to a portableIHS. The method comprises assembling a keyboard connector into thepalmrest assembly of a portable IHS, and inserting a substantially rigidkeyboard assembly connector tab, integral to a keyboard assembly andhaving electrical connections for the keyboard assembly, into thekeyboard connector of the palmrest assembly as part of a process ofaligning the keyboard assembly in its final position in the IHS. Thekeyboard assembly is secured to the IHS.

The disclosure also describes a method of inputting keystrokeinformation to a portable IHS. The method comprises translating userkeystrokes on a keyboard assembly into electrical signals, transmittingthe electrical signals through a connector from the keyboard assembly toa palmrest assembly comprising a keyboard controller, and decoding theelectrical signals in the keyboard controller into decoded keystrokes.The decoded keystrokes are transmitted over a first serial bus to amotherboard located in the portable IHS.

One other aspect of the disclosure relates to a portable IHS comprisinga housing, a motherboard located within the housing, a pointing deviceassembled to the housing to allow user pointing inputs, and a keyboardassembled to the housing to allow user keyboard inputs. The systemincludes at least one I/O controller, located off the motherboard, todecode the user pointing inputs and decode user keyboard inputs, and atleast one serial bus to communicate the decoded user pointing inputs andthe decoded user keyboard inputs to the motherboard.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an embodiment of an IHS.

FIG. 2 illustrates the external configuration of an embodiment of aportable IHS.

FIG. 3 contains an exploded view of the built-in user controls of anembodiment of a portable IHS, and their interconnections to themotherboard.

FIG. 4 shows the electrical connections and controllers for the built-inuser controls of an embodiment of a portable IHS.

FIG. 5 shows the electrical connections and controllers for the built-inuser controls of an embodiment of a portable IHS.

FIG. 6 contains an exploded view of the built-in user controls of theembodiment of FIG. 5.

FIG. 7 illustrates a detailed exemplary connection detail for a palmrestassembly according to an embodiment.

FIG. 8 shows details of a keyboard assembly according to an embodiment.

FIGS. 9, 10, and 11 a-11 c depict assembly details for a portable IHSaccording to an embodiment.

FIG. 12 is a block diagram illustrating an embodiment of an IHS.

DETAILED DESCRIPTION

For purposes of this disclosure, an IHS includes any instrumentality oraggregate of instrumentalities operable to compute, classify, process,transmit, receive, retrieve, originate, switch, store, display,manifest, detect, record, reproduce, handle, or utilize any form ofinformation, intelligence, or data for business, scientific, control, orother purposes. For example, an IHS may be a personal computer, anetwork storage device, or any other suitable device and may vary insize, shape, performance, functionality, and price. The IHS may includerandom access memory (RAM), one or more processing resources such as acentral processing unit (CPU) or hardware or software control logic,ROM, and/or other types of nonvolatile memory. Additional components ofthe IHS may include one or more disk drives, one or more network portsfor communicating with external devices as well as various input andoutput (I/O) devices, such as a keyboard, a mouse, and a video display.The IHS may also include one or more buses operable to transmitcommunications between the various hardware components.

FIG. 1 is a block diagram of one typical IHS. The IHS 100 includes aprocessor 102 such as an Intel Pentium series processor or one of manyother processors currently available. A memory I/O hub chipset 106(comprising one or more integrated circuits) connects to processor 102over a front-side bus 104. Memory I/O hub 106 provides the processor 102with access to a variety of resources. Main memory 108 connects tomemory I/O hub 106 over a memory bus. A graphics processor 110 alsoconnects to memory I/O hub 106, allowing the graphics processor tocommunicate, e.g., with processor 102 and main memory 108. Graphicsprocessor 110, in turn, provides display signals to a display device112.

Other resources can also be coupled to the system through memory I/O hub106, including an optical drive 114 or other removable-media drive, oneor more hard disk drives 116, one or more network interfaces 118, one ormore USB (Universal Serial Bus) ports 120, and a super I/O controller122 to provide access to user input devices 124, etc.

Not all IHSs include each of the components shown in FIG. 1, and othercomponents not shown may exist. Furthermore, some components shown asseparate may exist in an integrated package or be integrated in a commonintegrated circuit with other components. As can be appreciated, manysystems are expandable, and include or can include a variety ofcomponents, including redundant or parallel resources.

One physical configuration for an IHS 100 is as a “portable” or “laptop”computer. Such portable computers typically combine the processingcomponents of IHS 100 with a display, input devices, and a battery in acommon case, to provide a device that can be easily transported and usedalmost anywhere. As such, portable IHSs generally benefit fromminiaturization of size and weight of the IHS components. Referring toFIG. 2, an exemplary view of a portable computer IHS 100 is illustratedin a typical clamshell configuration. In this clamshell configuration, abottom shell 128 and a top shell 129 are hinged together with sufficientfriction such that the top shell can be positioned at a variety ofangles with respect to the bottom shell. The top shell can also beclosed and latched to the bottom shell for easy carrying and protectionof the display.

The top shell 129 houses display 112 and the bottom shell 128 typicallyhouses the remaining components of portable IHS 100. Most, if not all,of the user controls are typically mounted on or in the top surface 126of bottom shell 128. These controls can include a keyboard 130, atouchpad 140 and touchpad buttons 141, 142, a point stick 150 and pointstick buttons 151, 152, a power button 160, and ancillary and/or mediabuttons 170. The battery, electronics (including a motherboard to whichthe electronics are mounted or connected), and drive bays are locatedbelow the user controls within the bottom shell 128, and as such are notapparent in FIG. 2.

FIG. 3 contains an exploded view of some of the components of a portableIHS. FIG. 3 depicts the physical layout of the typical connectionsbetween the user input devices of a portable IHS and the motherboard. Amotherboard 200 has connectors 133, 145, and 155, to connect themotherboard respectively to keyboard 130, touchpad 140, and point stick150. The keyboard requires a large (greater than 25 conductors) ribboncable 131, the cable having an end connector 132 to mate with connector133 on motherboard 200. Ribbon cable 131 transfers signals from thekeyboard matrix to the motherboard and ultimately to the super I/Ocontroller (FIG. 1) for keystroke decoding. Additionally, a keyboardhaving a point stick 150 uses a smaller ribbon cable 153 having an endconnector 154 to mate with connector 155 on motherboard 200. Ribboncable 153 transfers signals from the point stick 150 to the motherboard.The touchpad 140 typically is combined with touchpad buttons 141, 142 ina common touchpad module, which uses another ribbon cable 143 having anend connector 144 to mate with connector 145. Ribbon cable 143 transferssignals from the touchpad module to the motherboard 200 and ultimatelyto the super I/O controller.

Other user inputs may also connect to the touchpad module. A point stickusually is accompanied by point stick buttons 151, 152, which arelocated below the spacebar of the keyboard and above the touchpad moduleon the palmrest. A ribbon cable 156 connects the point stick buttons tothe touchpad module. Also, ancillary/media button assembly 170 mayconnect by a ribbon cable 171 to the touchpad module.

FIG. 4 contains an electrical diagram 400 showing the electricalconnections corresponding to the physical arrangement of FIG. 3. Akeyboard matrix 330 on keyboard 130 couples through connector 133 to aset of matrix traces 312 on motherboard 200. The matrix traces 312connect in turn to an I/O controller 310, which detects keystrokes anddecodes them for processing by the IHS. The point stick 150, also onkeyboard 130, couples through connector 155 to a set of point sticksignal transfer traces 314 on motherboard 200. The point stick traces314 couple in turn to connector 145.

Two other sets of traces couple connector 145 to I/O controller 310.Touchpad controller traces 316 transfer signals that originate at atouchpad controller 350 to I/O controller 310. Ancillary button traces318 transfer signals that originate at ancillary/media button assembly170 to I/O controller 310.

A touchpad module 340 connects to motherboard 200 through ribbon cable143 and connector 145. A connector 344 on touchpad module 340 terminatesthe ribbon cable conductors to three sets of traces on a touchpad module340. A set of ancillary button signal transfer traces 348 routes signalsfrom connector 344 to another connector 346, which couples in turn toancillary button ribbon cable 171. A set of point stick traces 358routes point stick signals to touchpad controller 350 for decoding.Finally, a set of touchpad controller traces 360 route signals fromtouchpad controller 350 to connector 344.

Touchpad module 340 also contains the touchpad matrix 140 and touchpadbuttons 141, 142. A set of touchpad matrix traces 352 couple signalsfrom matrix 140 to touchpad controller 350 for decoding. A set oftouchpad button traces 354 couple signals from touchpad buttons 141, 142to touchpad controller 350.

Touchpad module 340 also contains a third connector 342 to connect toribbon cable 156 and point stick buttons 151, 152. A set of point stickbutton traces 356 on touchpad module 340 couple signals from the pointstick buttons to touchpad controller 350.

A number of deficiencies in this traditional user control interfacedesign have now been recognized. First, the keyboard requires arelatively large interconnect to the motherboard, for what are eachextremely low-frequency signal lines. Due to the central placement ofthe keyboard in the portable IHS, the keyboard connector 133 and largenumber of keyboard matrix traces 312 (see FIG. 3) typically occupyextremely valuable real estate on the central portion of themotherboard, and complicate circuit board trace routing. The keyboardmatrix also uses a large number of general purpose input output (GPIO)ports on the I/O controller, which could be used for advanceddiagnostics and other purposes were they available.

Second, different laptop chassis designs and sizes—and even regionalvariations of the same design—usually require a unique keyboard due todifferent motherboard keyboard connector locations. It would beadvantageous to decouple keyboard design from motherboard design toallow reuse of keyboards and keyboard components across multiple chassisand regions.

Third, current ribbon cable keyboard designs require a difficult “blind”assembly of the large connector. The keyboard is loosely placed over itsfinal position in the case while the connector is mated with themotherboard, such that the keyboard itself obscures and interferes withthe connection process. The process is unduly difficult for assemblers,and can result in damaged or improperly made connections. Users whoremove their own keyboards may either not make the connection properly,or not even realize they have to make the connection, resulting inunnecessary service calls and returns. The multiple other palmrestconnections (point stick, point stick buttons, touchpad) also slowassembly and are subject to damage or misalignment.

In systems with a point stick, connecting the point stick to themotherboard through one wire harness and then to the touchpad modulethrough a separate harness from the motherboard is undesirable as it iscomplex, subject to damage, and can result in reduced signal integrity.

These and other problems are addressed by features found in one or moreof the following embodiments. Generally, a keyboard controller isincorporated into the palmrest assembly (e.g., as part of the touchpadmodule) of a portable IHS. Various connections that are now required tothe motherboard are made instead to the palmrest assembly. For instance,a new connector design allows a tab on the keyboard to be inserted intoa socket in the palmrest assembly as part of mating the keyboard to thechassis, greatly simplifying assembly by, in essence, “docking” thekeyboard to the system. The keyboard controller in the palmrest assemblycan terminate many key press signals that were previously passed to themotherboard, and can communicate the content of the key press data withthe motherboard I/O controller over a serial data bus requiring only afew traces. Other features and advantages of the embodiments will becomeapparent in the following description.

FIG. 5 shows the electrical connections of a first portable IHSembodiment 500. Four assemblies are shown: a motherboard 502; a palmrestassembly 530; a keyboard assembly 580; and an ancillary button assembly600. Each will be described in turn.

Motherboard 502 includes an I/O controller 510 and other processingcomponents (processor, etc., not shown) for the portable IHS 500. Themotherboard 502 also includes a connector 504. Loopback traces 506 and508, keyboard controller bus traces 512, and touchpad controller bustraces 514 connect the I/O controller 510 to connector 504.

A ribbon cable or other wiring harness 520 couples connector 504 to acorresponding connector 532 on palmrest assembly 530. Harness 520includes loopback wires 522 and 524, having electrical continuityrespectively with loopback traces 506 and 508, keyboard controller buswires 526, having electrical continuity respectively with the keyboardcontroller bus traces 512, and touchpad controller bus wires 528, havingelectrical continuity respectively with the touchpad controller bustraces 514. The wiring harness also may include power connections (notshown) to power the components on the palmrest assembly.

Palmrest assembly 530 includes the motherboard connector 532, a touchpadcontroller 540, a touchpad matrix 542, touchpad buttons 546, a keyboardcontroller 550, a keyboard connector 552, an ancillary button connector570, and various circuit board traces to connect these components. Thesetraces will be described in detail after introduction of the keyboardassembly components.

Keyboard assembly 580 includes an integral connector 582, a point stick586, a keyboard matrix 590, point stick buttons 592, and various circuitboard traces.

Some of the connections to the touchpad controller are similar to thoseof FIG. 4. Touchpad controller 540 is coupled to connector 532 by a setof touchpad controller bus traces 538. A set of touchpad matrix traces544 couple signals from matrix 542 to touchpad controller 540 fordecoding. A set of touchpad button traces 548 couple signals fromtouchpad buttons 546 to touchpad controller 540.

Instead of coupling through the motherboard, the point stick 586 in FIG.5 couples directly from the keyboard assembly 580 to the palmrestassembly 530. Point stick signal traces 588 on keyboard assembly 580couple through connectors 582, 552 to a corresponding set of point sticksignal traces 558 on palmrest assembly 530. Touchpad controller 540couples to traces 558 to sense and decode point stick movements. Thisarrangement avoids the cumbersome point stick connection arrangement ofFIG. 4. Should the keyboard assembly not include a point stick, traces588 may be left unconnected, or removed from the assembly, with thecorresponding connector leads in connector 582 left unused.

The arrangement of point stick buttons 592 also differs from FIG. 4. Onkeyboard assembly 580, point stick buttons 592 are implemented onkeyboard assembly 580. Dedicated point stick button lines, shown in thisembodiment as bundled with the keyboard matrix row and column lines 594,596, serve the point stick buttons 592. In an embodiment, one or morekeyboard matrix row or column lines could be shared between the pointstick buttons and keyboard rows or columns. In one embodiment, thematrix lines serving the point stick button locations exist whether thekeyboard assembly includes point stick buttons or not. The physicalbuttons are, however, not part of the assembly in some configurations,with the underlying point stick button locations covered and leftinactive.

The keyboard matrix 590, including portions of the matrix serving pointstick buttons 592, is coupled via keyboard matrix row lines 594 andkeyboard matrix column lines 596, through connector 582 and connector552, to palmrest keyboard matrix row traces 560 and palmrest keyboardmatrix column traces 564. Keyboard matrix column traces 564 join withancillary button column traces 574 to form a combined set of columntraces 562, which couple to keyboard controller 550 (i.e., ancillarybuttons 600 share some or all of their column traces with keyboardcolumns). Keyboard matrix row traces 560, as well as ancillary buttonrow trace(s) 572, also couple to keyboard controller 550. Keyboardcontroller 550 decodes keystrokes and ancillary button presses usingsignals received via traces 560, 562, and 572.

Ancillary button row traces 572 and column traces 574 couple toancillary button assembly 600 via a connector 570 on palmrest assembly530, a wiring harness/cable 598, and a connector 602 on ancillary buttonassembly 600. Note that different ancillary button assemblies could beused with different button assignments, with appropriate firmware,and/or palmrest module 530 may be used without an ancillary buttonassembly. The ancillary button assembly (as well as keyboard assembly580) may also include Light Emitting Diodes (LEDs) that are activated,e.g., from keyboard controller 550 outputs to indicate various functionsor provide illumination of buttons, etc.

One feature shown in FIG. 5 is a loopback diagnostic capability. Theloopback diagnostic capability uses one or more of I/O controller 510,touchpad controller 540, and keyboard controller 550 to test theintegrity of the connections between the motherboard and the palmrestassembly, the palmrest assembly and the keyboard assembly, and thepalmrest assembly and the ancillary button assembly. This feature uses,e.g., freed GPIOs on I/O controller 510 and/or free GPIOs on controller540 and/or controller 550, in conjunction with loopback connectionsthrough the connectors. For instance, the previously described loopbacktraces 506, 508 couple through wires 522, 524 of harness 520 to palmrestassembly 530. On the circuit board of palmrest assembly 530, theconnector 532 connections to wires 522, 524 are shorted together by atrace 534. This allows I/O controller 510 to sense and diagnose a lackof connection between motherboard 502 and palmrest assembly 530. In oneembodiment, the loopback connections are spaced near opposite ends ofconnectors 504 and 532, such that a connector that is partially insertedat an angle, with connections made at one end but not the other, can bedetected. The I/O controller 510 notifies processing elements of the IHSwhen the palmrest assembly is not properly connected.

In FIG. 5, keyboard controller 550 manages similar loopback detectioncircuits for the connections to keyboard assembly 580 and ancillarybutton assembly 600. For keyboard assembly 580, a GPIO of keyboardcontroller 550 is coupled to two loopback traces 554 and 556. Loopbacktraces 554 and 556 couple through connectors 552 and 582 to the keyboardassembly, where a trace 584 shorts the loopback traces together when thekeyboard is connected properly. When the keyboard controller fails tosense a short, it notifies I/O controller 510 of a keyboard disconnecterror.

In a similar manner, another GPIO of keyboard controller 550 is coupledto two loopback traces 566 and 568. Loopback traces 566, 568 couplethrough connector 570, harness 598, and connector 602 to the ancillarybutton assembly, where a trace 604 shorts the loopback traces togetherwhen the ancillary button assembly is connected properly. When thekeyboard controller fails to sense a short, it notifies I/O controller510 of an ancillary button disconnect error.

FIG. 6 contains an exploded view of some of the components of a portableIHS according to an embodiment such as the FIG. 5 embodiment. FIG. 5depicts the physical layout of the connections between the user inputdevices of the portable IHS and a motherboard 610. Palmrest assembly 530and keyboard assembly 580 connect or “dock” directly to each other,making electrical connections in the process for all keyboard and pointstick functions. Ancillary button assembly 600 connects to palmrestassembly 530 via ribbon cable/wiring harness 598. Palmrest assembly 530connects to motherboard 610 via ribbon cable/wiring harness 520, whichhas a connector 612 that mates with connector 504 on motherboard 610.Generally, ribbon cable/wiring harness 520 contains only a small numberof wires as compared to the three motherboard cables of the FIG. 3configuration. This allows connector 504 to be smaller, more flexible inpositioning, and capable of positioning nearer the periphery of themotherboard. The keyboard can also be removed without disturbing anyconnections to the motherboard.

FIG. 7 depicts an exemplary embodiment 700 of electrical connections toa palmrest assembly 740. These connections are made at a keyboardconnecting tab 710, an ancillary connector 720, and a motherboardconnector 730. At the keyboard connecting tab 710, connections exist fora keyboard loopback function, point stick termination, point stickbuttons, key columns, and key rows (e.g., auxiliary keys, function keys,number keys, “QWERTY” keys, “ASDFG” keys, “ZXCVB” keys, and space barrow keys). At the ancillary connector, connections exists for anancillary loopback function, a key column subset, and a media/ancillarybutton row. At the motherboard connector, connections exist for apalmrest loopback function, power, touchpad I/O, and keyboard I/O. Somefunctions may require more connections than are shown, depending onimplementation. Other functions, such as status LEDs, may also besupported through the connections.

In one embodiment, the connection between a palmrest assembly and akeyboard assembly is made using a rigid connection tab that isfabricated directly into the keyboard assembly. Such a structure isshown in FIG. 8, which depicts a lower central portion of a keyboardassembly 580, with the keys removed. The keyboard assembly contains alower support 830, e.g., made of a rigid material such as stampedaluminum sheet. During fabrication of lower support 830, a connectiontab 800 with insertion guides 802, 804 is formed.

A keyboard matrix layer 832 overlies lower support 830. The keyboardmatrix layer includes row and column traces and appropriate insulatinglayers. The row and column traces, as well as other traces such as thoseto point stick 586, route to edge contacts 840 on connection tab 800. Arubber sheet, including rubber domes 810, 812, 814, 816, 818, 820, 822,824, and 826, overlies the keyboard matrix layer 832. Each rubber domeis placed at the location of a key (not shown) that will exist in thefinal assembly. A carbon center underlies each rubber dome, such thatwhen an overlying key is depressed, a plunger on the key pushes down onthe dome, causing the carbon center to complete a connection with acorresponding row line and column line.

In some embodiments, the same basic assignment of edge connectors 840 isused for point stick and non-point stick versions of the keyboardassembly. Rubber domes 810 and 812 may be non-existent in the non-pointstick version, or domes 810 and 812 may be made nonfunctional, e.g., bycovering them with a solid member and/or by removing their carboncenter.

FIG. 9 shows a bottom view of keyboard assembly 580 and a palmrestassembly 530, illustrating an assembly sequence. An expanded bottom viewof one section 900 of palmrest assembly 530 is also illustrated. Section900 includes a floating docking port 920 to receive keyboard connectiontab 800 and its insertion guides 802 and 804. Floating docking port 920includes a set of contacts 910 to make with edge contacts 840 (FIG. 8)of keyboard assembly 580 when keyboard connection tab 800 is fullyinserted. Floating docking port 920 preferably flexes upwards (down inFIG. 9) to allow the keyboard connection tab 800 to be tilted downwardsslightly for insertion. Floating docking port 920 preferably also allowsslight transverse shifts to accommodate alignment of the keyboardassembly with the IHS chassis. To accommodate these features, contacts910 can connect to the circuit board of palmrest assembly 530 via aflexible flat cable or the like.

One other feature shown in FIG. 9 is a T-shaped slot 860 in the rigidlower member of keyboard assembly 580. Slot 860 facilitates assembly,and will be explained further below with respect to FIGS. 11 a-11 c.

FIG. 10 shows further details of the assembly of a portable IHS 950according to an embodiment. In FIG. 10, palmrest assembly 530 has beenpreviously assembled to a lower clamshell chassis 955 of portable IHS950. The upper surface of chassis 955 contains an opening 960 to receivekeyboard assembly 580. Opening 960 includes a depressed lip 962 tosupport keyboard assembly 580 in the final assembly.

Keyboard assembly 580 is assembled to portable IHS 950 by first engagingkeyboard connection tab 800 with the floating docking port on the bottomside of palmrest assembly (see FIG. 9) and sliding the keyboard assemblytowards the palmrest assembly. Keyboard assembly 580 includes locatortabs 970, 972, 974 to engage respectively with three locator slots 964,966, and 968 in the lower edge of depressed lip 962, as the keyboardassembly nears its final alignment. Fastener tabs 976, 978, 980, locatedalong the top edge of keyboard assembly 580, can then receive fastenersto secure the keyboard assembly to the portable IHS.

FIGS. 11 a-11 c show an additional keyboard retention feature useful inembodiments. FIGS. 11 a-11 c show a magnified view of one section ofchassis 955 and one section of keyboard assembly 580 during the finalassembly process. Keyboard detail is omitted such that the T-shaped slot860 in the rigid lower member of keyboard assembly 580 is visible.Fastener tabs 980 and 978 are also visible, with their respectivefastener holes 982 and 984.

The magnified section of chassis 955 includes additional details for thedepressed lip 962 of opening 960. Lip 962 includes fastener mountingholes 986, 988, which will align with fastener holes 982 and 984 in thefinal assembly. Lip 962 also includes a mushroom connector 990protruding from its bottom surface.

In FIG. 11 b, keyboard connection tab 800 has been engaged sufficientlywith the floating docking port on the bottom side of the palmrestassembly (see FIGS. 9 and 10) to allow the keyboard assembly 580 to lieflat against lip 962. Before the keyboard assembly can lie flat,mushroom connector 990 must align with the wider section of T-shapedslot 860, such that the mushroom connector can protrude through theslot. In this position, tabs 800, 970, 972, and 974 are not yet fullyengaged, and fastener holes 982 and 984 are not yet aligned withfastener mounting holes 986, 988.

In FIG. 11 c, the keyboard assembly has been fully engaged by sliding ittowards the lower edge of lip 962. In the fully engaged position,mushroom connector 990 is retained in the narrower portion of T-slot860. The mushroom prevents lifting of the upper edge of keyboardassembly 580 with the assembly in final alignment. In this alignment,fasteners can now be inserted into fastener holes 982 and 984 andsecured to fastener mounting holes 986, 988.

FIG. 12 illustrates a block diagram for a portable IHS 1000 includingfeatures described above. Processor 102, frontside bus 104, memory I/Ohub 106, main memory 108, graphics processor 110, display device 112,optical drive 114, hard disk drive 116, network interfaces 118, and USBports 120 function in similar fashion to their counterparts in FIG. 1. Asuper I/O controller 1010 communicates upstream with memory I/O hub 106,and communicates downstream with a touchpad controller 1020 and akeyboard controller 1030. The connections to controllers 1020 and 1030are made across a palmrest interface 1014. A palmrest loopback circuit1012 is also coupled across palmrest interface 1014, and connects tosuper I/O controller 1010.

Touchpad controller 1020 communicates with a touchpad 1022, andcommunicates with a point stick 1024 across a keyboard interface 1026.

Keyboard controller 1030 communicates with a keyboard 1032 across thekeyboard interface. A keyboard loopback circuit 1036 is also coupledacross keyboard interface 1026, and connects to keyboard controller1030. Keyboard controller 1030 also communicates with ancillary buttons1034 across an ancillary interface 1038. An ancillary loopback circuit1040 is also coupled across the ancillary interface 1038, and connectsto keyboard controller 1030.

Various features of the embodiments above can be combined in a varietyof ways, or implemented using other mechanical and/or electricalconstructs. Embodiments can be implemented with a variety of userselection controls. A keyboard assembly that will never support a pointstick or point stick buttons need not have edge contacts and matrixtraces for point stick controls. Likewise, a palmrest assembly need nothave a touchpad and related electronics, and could have other selectioncontrols such as a track ball. Other connections, such as a power buttonconnection, could route directly from the keyboard through the palmrestassembly to the motherboard. Key switches other than rubber domeswitches can be used to translate user keystrokes and button pressesinto electrical signals.

In some embodiments, keyboard commonality across platforms is aided bydimensionally referencing the keyboard “center” (intersection of “G”,“B”, and “H” keys) to the touchpad. Various chassis can then be providedto accept the same basic keyboard layout.

Although illustrative embodiments have been shown and described, a widerange of other modification, change and substitution is contemplated inthe foregoing disclosure. Also, in some instances, some features of theembodiments may be employed without a corresponding use of otherfeatures. Accordingly, it is appropriate that the appended claims beconstructed broadly and in manner consistent with the scope of theembodiments disclosed herein.

1. A portable information handling system comprising: a housing; amotherboard located within the housing; a palmrest assembly coupled tothe housing and comprising a keyboard controller; a keyboard assemblycoupled to the palmrest assembly such that the keyboard controller isoperable to receive keystroke signals from the keyboard assembly,wherein the coupling between the keyboard assembly and the palmrestassembly comprises a keyboard assembly connector on the keyboardassembly and a palmrest assembly connector on the palmrest assembly forreceiving the keyboard assembly connector, the palmrest assemblyconnector operative to receive the keyboard assembly connector while thepalmrest assembly is assembled to the housing; and a first bus couplingthe keyboard controller to the motherboard, wherein the keyboardcontroller is operable to receive the keystroke signals from thekeyboard assembly, decode the keystroke signals, and transmit thedecoded keystroke signals to the motherboard over the first bus.
 2. Theportable information handling system of claim 1, wherein the palmrestassembly comprises a touchpad module.
 3. The portable informationhandling system of claim 2, wherein the touchpad module comprises atouchpad matrix, a plurality of touchpad buttons, and a circuit board,wherein the touchpad matrix, touchpad buttons, and keyboard controllerare coupled to the circuit board.
 4. The portable information handlingsystem of claim 3, further comprising: a touchpad controller coupled tothe circuit board and electrically coupled to the touchpad matrix andtouchpad buttons through the circuit board.
 5. The portable informationhandling system of claim 4, further comprising: a second bus couplingthe touchpad controller to the motherboard, the first and second busesassembled in a common wire assembly for connection to the motherboard.6. The portable information handling system of claim 4, wherein thekeyboard assembly comprises a point stick assembly, the point stickassembly coupled through the keyboard assembly to the palmrest assemblysuch that the touchpad controller receives point stick signals from thepoint stick assembly.
 7. The portable information handling system ofclaim 4, wherein the keyboard assembly comprises a plurality of pointstick buttons, the point stick buttons coupled through the keyboardassembly to the palmrest assembly such that at least one of the touchpadcontroller and the keyboard controller receives point stick buttonsignals from the point stick buttons.
 8. The portable informationhandling system of claim 7, wherein the point stick buttons share atleast one signal line to the palmrest assembly with at least one key onthe keyboard assembly.
 9. The portable information handling system ofclaim 1, further comprising: an ancillary button assembly coupled topalmrest assembly such that the keyboard controller receives buttonpress signals from the ancillary button assembly.
 10. The portableinformation handling system of claim 9, wherein the ancillary buttonassembly shares at least one signal line to the keyboard controller onthe palmrest assembly with the keyboard assembly.
 11. The portableinformation handling system of claim 9, wherein the coupling to theancillary button assembly comprises at least one loopback connection tothe keyboard controller.
 12. The portable information handling system ofclaim 1, wherein the motherboard comprises an input/output (I/O)controller, and wherein the coupling from the palmrest assembly to themotherboard comprises at least one loopback connection to the I/Ocontroller.
 13. The portable information handling system of claim 1,wherein the keyboard assembly is mounted to the housing, and wherein thepalmrest assembly connector articulates with respect to the palmrestassembly to receive the keyboard assembly connector tab prior to thekeyboard assembly being mounted to the housing.
 14. A method ofinputting keystroke information to a portable information handlingsystem, the method comprising: providing a keyboard assembly coupled toa palmrest assembly through a connection of a keyboard assemblyconnector on the keyboard assembly and a palmrest assembly connector onthe palmrest assembly that receives the keyboard assembly connectorwhile the palmrest assembly is assembled to the housing; translatinguser keystrokes on a keyboard assembly into electrical signals;transmitting the electrical signals from the keyboard assembly to akeyboard controller located in the palmrest assembly through theconnection of the keyboard assembly connector and the palmrest assemblyconnector; decoding the electrical signals, using the keyboardcontroller, into decoded keystroke signals; and transmitting the decodedkeystroke signals over a first serial bus that extends between thepalmrest assembly and a motherboard that is located in the portableinformation handling system.
 15. The method of claim 14, furthercomprising: translating user ancillary button presses on an ancillarybutton assembly to electrical signals; transmitting the electricalsignals through a connection from the ancillary button assembly to thepalmrest assembly; decoding the electrical signals from the ancillarybutton assembly in the keyboard controller into decoded button pressinformation; and transmitting the decoded button press information overthe serial bus to the motherboard.
 16. The method of claim 15, whereinthe electrical signals from the keyboard assembly and ancillary buttonassembly share at least some common connections in the palmrest assemblyto the keyboard controller.
 17. The method of claim 14, furthercomprising: translating user inputs to a point stick affixed to thekeyboard assembly into electrical signals; transmitting the point stickelectrical signals through the keyboard assembly to palmrest assemblyconnector; decoding the point stick electrical signals in a touchpadcontroller on the palmrest assembly into decoded point stickinformation; and transmitting the decoded point stick information over asecond serial bus to the motherboard.
 18. The method of claim 17,wherein the first and second serial buses share a common multiconductorcable coupling the palmrest assembly to the motherboard.
 19. The methodof claim 17, further comprising: translating user button presses on aplurality of point stick buttons affixed to the keyboard assembly intopoint stick button electrical signals; transmitting the point stickbutton electrical signals through the keyboard assembly to palmrestassembly connector; decoding the point stick button electrical signalsin one of the keyboard controller and touchpad controller into decodedpoint stick button information; and transmitting the decoded point stickinformation over one of the first and second serial buses to themotherboard.
 20. A portable information handling system comprising: ahousing; a motherboard located within the housing; a palmrest assemblycoupled to the housing and comprising a keyboard controller; a keyboardassembly coupled to the palmrest assembly such that the keyboardcontroller receives keystroke signals from the keyboard assembly,wherein the coupling between the keyboard assembly and the palmrestassembly comprises a connector tab on the keyboard assembly and a socketfor receiving the connector tab on the palmrest assembly, the socketoperative to receive the keyboard assembly connector tab while thepalmrest assembly is assembled to the housing; and a first bus couplingthe keyboard controller to the motherboard through the palmrestassembly, the keyboard controller transmitting decoded keystrokes to themotherboard over the bus.
 21. The portable information handling systemof claim 20, wherein the keyboard assembly is mounted to the housing,and wherein the socket articulates with respect to the palmrest assemblyto receive the keyboard assembly connector tab prior to the keyboardassembly being mounted to the housing.